fix(docs): Do correct link

cl/api/templates/rest-docs-vlatest.html

@@ -28,7 +28,7 @@ <h1 id="about">REST API &ndash; v4.0</h1>
 
     <p class="lead">APIs for developers and researchers that need granular legal data.
     </p>
-    <p class="alert alert-warning">A new version of the API is now live! Please read <a href="{% url "migration_guide" %}">our migration guide</a> to update. The <a href="{% url "rest_docs" version="v4" %}">old version of the documentation</a> is maintained for migration purposes only.
+    <p class="alert alert-warning">A new version of the API is now live! Please read <a href="{% url "migration_guide" %}">our migration guide</a> to update. The <a href="{% url "rest_docs" version="v3" %}">old version of the documentation</a> is maintained for migration purposes only.
     </p>
     <p>After more than a decade of development, these APIs are powerful. Our <a href="{% url "case_law_api_help" %}">case law API</a> was the first. Our <a href="{% url "pacer_api_help" %}">PACER</a> and <a href="{% url "oral_argument_api_help" %}">oral argument</a> APIs are the biggest. Our <a href="{% url "webhooks_getting_started" %}">webhooks</a> push data to you. Our <a href="{% url "citation_lookup_api" %}">citation lookup tool</a> can fight hallucinations in AI tools.
     </p>